Carburizing compound



UNITED- STATES PATENT OFFICE.

JOSEPH HERMAN SCHMITT, OE WEEHE WKEN, NEW JERSEY.

CAHIBU'RIZING coMrouNn.

No Drawing.

To all whom it They concern:

Be it known that I, Josnrrr HERMAN SCHMITT, acitizen of the United States, and resident of lVeehawken, in the county of Hudson and State of'New Jersey, have invented certain new and useful Improvements in Carburizing Compounds, of which the following is a specification.

This invention relates to the carburizing of steel by dry packing and discloses a new and improved compound therefor.

As the expense and time incident to the case hardening process are material items in the case, many attempts have been made to decrease the time of penetration of the carbon to a predetermined depth. Various materials have been used in making carburizing compounds to accomplish this result, in general, consisting of carbon mechanically mixed with an energizer. Sub stances such as hydrocarbon oils and oxidized vegetable oils are sometimes added, the first to prevent dusting and the latter to prevent separation of the energizer from the carbon due to the difference in specific gravities, but such materials have only been effec tive for the first heating. As it is customary to re-use the compound with the addition of fresh compound and as the hydrocarbon oils having been volatilized by the heat the old material is dusty and the energizer that remains separates out and is no longer properly mixed with the carbon.

The objects of this invention are to provide a carburizing compound that will de; crease the time of penetration to a predetermined depth and one that can be made from materials of which there is a plentiful supply and one that can be more effectively re-used in that the energizer that remains does not become separated out and one that does not become dusty after the first use.

I have found that a carburizing compound composed of charcoal, petroleum coke or retort carbon, petroleum shale and calcium cyanamid is such a form of carburizing eompound. The calcium cyanamid is particularly effective in reducing the time of pene- Specification of Letters Patent. Patented Feb. 28, 1922.

Application filed January 11, 1921; Serial No. 436,600.

tration of. the carbon to a predetermined depth of from 10 to per cent, depending upon a number of variables such as, the kind of steel,the shape of the part, the type of carburizing box, etc.

The powdered petroleum shale not only acts as a carburizer, but also has an afiinity for the petroleum coke and the cyanamid to prevent dusting, due principally to the oil contained in the shale. This material is of particular importance for this purpose as it retains its properties after having been used. The 011 content is only partlally lost upon a heating. As it is the customary practice to re-utillze the used compound'with the addition of a small amount of fresh material it is therefore, desirable to have a compound that will not become dusty after the first heatin and the powdered shale accomplishes in diminishing amounts as it is increased in quantity.

hat I claim is :7

1. A carburizing compound comprising carbon, petroleum shale and calcium oyanamid.

2. A carburizing material comprising, charcoal,retortcarbon, petroleum shale and calcium cyanamid.

3. A carburizing material comprising charcoal, petroleum coke, powdered petroleum shale and calcium cyanamid.

Signed at New York in the county of New York and State of New York this 10th day of January A. D. 1920.

JOSEPH HERMAN SCHMITT. 

